Tilting chair

ABSTRACT

An improved chair for combined office and rest use is disclosed which includes a support member carried by a support leg and having its front end portion extended obliquely upward, a chair seat pivotably mounted at its front edge to the front end portion of the support member, a rotary shaft rotatably mounted on the chair seat transversely thereacross and having an operation handle fixedly secured thereto. A cam is fixedly secured to the rotary shaft and has a hook-shaped slot opening for slidable cooperation relative to a fixed pin transversely traversing the slot and mounted on the support member, and resilient means are interposed between the chair seat and its support member. Normally the pin is engaged within the hook tip portion of the cam slot opening to lock the chair seat in a substantially horizontal position. A rotational operation of the handle is accompanied with a disengagement of the pin from the hook tip portion of the cam slot, and thereby the chair seat becomes rockable about the pivot at the front end portion of the support member aided by slight shifting of the occupant&#39;&#39;s weight.

United States Patent [72] Inventor Yoshlomt Yamaguchl FOREIGN PATENTS Tkynlapan 669 160 12/1965 B61 glum 297/328 [211 APPL 8361822 878 71s 10/1961 Great Britain 297/313 22 Filed Dec.22,1969 5 patented Dem M. 197] Primary Examiner-Mar on Parsons, Jr. I 73 I Atsignee Kabunhlkl Keisha llmal Selnkusho mmmeywenderth Lmd & Ponack Tokyo,,lapnn ABSTRACT: An 1m roved chair for combined office and rest P use is disclosed which includes a support member carried by a 5 TILTING CHAR support leg and having its front end portion extended oblique- 7 Chums. 5 Drawlna Flg ly upward, a chair seat pivotably mounted at its front edge to the front end portion of the support member, a rotary shaft [52] U-S- C11 248/384, otau bly mounted on the chair eat transversely [hereacross 297/323 and having an operation handle fixedly secured thereto. A In! cam is fixedly ecured to the rotary shaft and has a hook- 0 Search shaped slot opening for slidable cooperation relative to a fixed 384, 2 7/ 26, 327, 32 in transversely traversing the slot and mounted on the sup- 270, 269 port member, and resilient means are interposed between the 56 chair seat and its support member. Normally the pin is en- 1 References Cited gaged within the hook tip portion of the cam slot opening to UNITED STATES PATENTS lock the chair seat in a substantially horizontal position. A 1,174,429 3/1916 McCrea 248/384 rotational operation of the handle is accompanied with a dis- 2,687,166 8/1954 Hamilton... 297/326 engagement of the pin from the hook tip portion of the cam 2,698,649 1/1955 Hopkes 297/269 slot, and thereby the chair seat becomes rockable about the 2,748,835 6/1956 Barecki 248/397 pivot at the front end portion of the support member aided by 2,850,081 9/1958 Dillon..... 248/397 slight shifting of the occupants weight. 3,480,249 11/1969 Lie 297/328 5 I T I I a I l 1 5 lo I PATENIEDnmmsn 3,627,252

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sumaufa YOSIIIOMI YAMAGUCHIL, INVENTOR ATTORNEY 23 .TIIL'lIlING CHAIR The present invention relates in general to a chair, and more particularly to an improvement in a tiltable chair for combined office and rest use.

In the daily life, one would take two alternative postures, one for office work and the other for rest, and accordingly chairs are grouped into those for office use and those for rest use so as to be adapted for the respective postures.

Therefore, it is desirable to make one chair serve the requirements for both office use and for rest use, respectively.

However, said respective requirements are quite different from each other. In more particular, upon working in an office a position of the chair seat surface having an inclination with respect to the horizontal plane of 3-5, that is, almost near to the horizontal plane, is more efficient, whereas upon taking a rest, a more inclined position of the chair seat surface (an inclination with respect to the horizontal plane of ll5) is preferable.

In the chairs according to the prior art, there are various chairs in which the seat is made rockable so that the seat surface may be inclined. However, in such type of prior art chairs, the center of the rocking motion of the chair seat was located in the middle of the seat, and consequently they had a disadvantage that when the chair seat surface was inclined, the front edge of the seat surface was raised resulting in change of the effective height of the chair.

The present invention has been proposed in view of the above-mentioned background of the art, and one of the principal objects of the present invention is the provision of an improved chair adapted both for office use and for rest use.

Another object of the present invention is the provision of an improved chair in which the inclination adjustment of the chair seat may be accomplished in a simple manner.

Another object of the present invention is the provision of an improved chair in which when the chair seat is inclined, the vertical position of the front edge of the seat is not changed and thereby the chair seat may take a position preferable for rest use.

Still another object of the present invention is the provision of an improved chair which can be automatically returned from one position for rest use to the other position for office use.

In order to achieve the aforementioned various objects, the chair according to the present invention is characterized in that said chair comprises a support member carried by a support leg and having its front end portion extended obliquely upward, a chair seat pivotably mounted at its front edge to the font end portion of said support member, a rotary shaft rotatably mounted on said chair seat transversely thereacross and having an operation handle fixedly secured thereto, a cam fixedly opening, which is cooperable with a transversely disposed pin traversing said slot opening in said cam and which pin is transversely mounted in a fixed manner on said support member. Suitable resilient means is inserted between said chair seat and said support member to bias and tilt the chair seat backwardly when in the unhooked condition. For normal business use, said pin is engaged with the hook tip portion of said slot opening in said cam to lock said chair seat in a substantially horizontal position; and a rotational operation of said handle is accompanied with disengagement of said pin from the hook tip portion of said slot opening in said cam, and thereby said chair seat becomes rockable about the pivot at the front end portion of said support member.

In the chair according to the present invention, as described above, normally the pin transversely mounted on the support member of the chair seat is engaged with the hook tip portion of the slot opening in the cam which is fixedly secured to the rotary shaft which is, in turn, transversely mounted on the chair seat, so that the chair seat may be locked in the substantially horizontal position that is adapted for office use.

Now, upon taking a rest, the rotary shaft is turned by operating the operation handle which is fixedly secured to said rotary shaft while one is still sitting on the chair, and thus the hook tip portion of the slot opening in the cam which is fixedly secured to the rotary shaft is disengaged from said pin. Then the chair seat swings to an inclined position about the pivot on the support member, and due to the resilient means interposed therebetween, the chair seat is resiliently supported at an inclination angle that is adapted for rest.

According to the present invention, since the front edge of said chair seat is pivotably supported at the front end portion of the support member which extends obliquely upward, even when the seat is inclined as described above, the position of said front edge is not changed resulting, in no change in the effective height of the chair, so that the feeling in use is very comfortable.

Other objects and features of the present invention will become apparent from the following description with reference to its preferred embodiment illustrated in the drawings, in which:

FIGS. l and 2 are front and side views, respectively, of the chair according to the present invention showing the posture for office use,

FIGS. 3 and 4 are enlarged longitudinal cross-sectional side views of an essential part of said chair, respectively, in the position for office use and in the position for rest use, and

FIG. 5 is a longitudinal cross-sectional back view showing an essential part of the inclination adjusting mechanism of said chair.

in the drawings, reference numeral 1 designates a support leg of a chair, at the top of which is rotatably mounted a support member 2 having a channel-shaped cross section.

The front end portion of the support member 2 extends obliquely upward, and at this portion is mounted a bracket 4 provided on the lower surface of the front edge of the chair seat 3 rotatably in the vertical plane about a pivot 5.

Numeral 6 designates a compression coil spring inserted between the seat 3 and the bottom surface of the support member 2, the upper end of which fits onto a protrusion 7 projecting from the back or lower surface of the Seat 3, and the lower end of which is supported by a cup-shaped spring bearing h. Into a hole provided at the bottom of said spring bearing 8 is fitted a tip of reduced diameter of an adjusting bolt 10 which is threaded into a nut 9 which is in turn welded to the bottom surface of the support member 2, and thus the spring bearing 8 is supported by the shoulder of said bolt 10. Accordingly, the resilient force of the coil spring 6 can be adjusted by the operation of the adjusting bolt 10.

A rotary shaft 12 is rotatably mounted in a bracket lll provided on the lower surface of the chair seat at a position behind said protrusion 7, and an operation handle 13 which is fixedly secured to said shaft 12 extends along the side of the seat 3 to locate its tip portion in the proximity of its front edge.

In addition, an upper end of a cam 11-4 is fixedly secured to said rotary shaft 12, and said cam 14 is provided with a L- shaped slot opening 1 having its lower end portion extending forward in a hooklike manner. Into said slot opening 15 is slidably fitted a pin 16 which is transversely mounted between opposite side pieces of the support member 2 having a channel-shaped cross section. When using the illustrated chair for office work, the pin 16 is engaged with the hook tip portion of the slot opening 15 in the cam 14 to hold the chair seat 3 in the substantially horizontal position adapted for office use. (See FlG. 3.)

In the figures, reference numeral 17 designates a chair back, numeral 18 designates a back frame, and numeral l9 designates a castor.

Since the illustrated chair is formed in. the above-mentioned manner, when the user wishes to take a rest, he will turn the operation handle ll3 upward while he is sitting on the chair. Then the cam M will turn together with the rotary shaft 12 in the clockwise direction to disengage the hook tip portion of the slot opening 15 from the pin 16, and thus due to the body weight of the user, the chair seat 3 will swing in the clockwise direction about the pivot support 5 mounted to the front end portion of the support member 2 as it is guided by means of the longitudinal portion of the L-shaped slot opening 15 and the pin 16 to an inclined position. (See FIG. 4.)

At this moment, by preliminarily adjusting the resilient force of the coil spring 6 to an appropriate amount, the chair seat 3 can be resiliently supported by the coil spring 6 so as to take an inclination angle of l"l5 that is adapted for a rest posture. Furthermore, then the chair seat 3 is inclined about the pivot support 5 provided along its front edge for mounting to the support member 2, so that the height of the front edge of the seat 3 is not changed.

in order to restore the chair seat 3 from said rest position to the original oflice use position, it is only required for the user to raise his waist slightly from the seat 3 or to stand up. Then due to the weight of the operation handle 13, the rotary shaft 12 restores its original position, where the pin 16 is engaged with the hook tip portion of the hook-shaped slot opening in the cam 14, and thus the chair seat 3 can automatically restore to its original position, that is, the position for office use.

While the present invention has been described above in connection to its preferred embodiment, of course, the present invention should not be limited only to such an embodiment, but various changes in design could be made within the scope of the invention without departing from the spirit of the invention.

What is claimed is;

l. A selectively tiltable chair characterized in that said chair is tiltable between a normally level upright business use posture and a tilted back more restful use posture, comprising a support member carried by a single pedestal support leg disposed generally centrally thereof and having a front end portion extended obliquely upward; a chair seat pivotably mounted near a front edge to said front end portion of said support member; a rotary adjustment shaft rotatably mounted on and beneath said chair seat transversely thereacross and having an operation handle fixedly secured thereto; a cam fixedly secured to said rotary shaft for movement therewith and having a generally hook-shaped camming slot; a rigid pin fixedly mounted on said support member transversely to the plane of the cam slot with which said cam slot slidably cooperates; and resilient means engagingly interposed between said chair seat and said support member normally tending to bias said seat upwardly to the level use; said pin is normally engaged with the hook tip portion of said cam slot when said seat is in the normal level use to thereby lock said chair with the seat in a substantially horizontal position; and

said cam slot being disengageable from said pin responsive to rotational operation of said handle with disengagement of said pin from the hook tip portion of said cam slot, whereby said chair seat is rockable about the pivot at the front end portion of said support member between said two postures with relatively insignificant difference in change of elevation of the front edge of said seat between the two postures.

2. A chair as defined in claim 1 wherein said hook-shaped slot cam is more L-shaped with the small leg or base of the L directed to the front edge of the seat to constitute the hook portion, and with the longer longitudinal portion disposed generally upright, both portions being slidably cooperable with said transversely mounted pin, particularly when the seat is released into the tilted back more restful use position.

3. A chair as defined in claim 1 wherein said rotary adjustment shaft is disposed generally medially between the front and a back edge of said seat, and said rigid pin is disposed slightly forward of and generally parallel to said adjustment shaft beneath said chair seat.

4. A chair as defined in claim 1 wherein said operation handle is extended from said rotary adjustment shaft forwardly along the side of the chair seat terminating near the front edge of said chair seat, and said chair seat resilient means, operation handle and adjustment shaft are so related that upon removal or forward shifting of the chair occupant's weight forwardly from a relaxed position, the chair seat will automatically return to the normal seat level position.

A chair as defined in claim 1 wherein said support member is formed to have an upwardly open, elongated channel-shaped cross section having a bottom wall and opposite side flanges projecting upwardly therefrom, and directed in a fore and aft direction; said resilient means being interposed between said bottom wall of said support member and the lower surface of the chair seat, and said fixed pin is transversely mounted between the opposite side flanges of said support member while passing through said cam slot.

6. A chair as defined in claim 1 wherein said resilient means includes a compression coil spring, and means for adjusting the resilient force thereof.

7. A chair as defined in claim I wherein said support, resilient means and chair seat are so related that the chair seat is inclined rearwardly at a shallow angle of 3-5 with respect to the horizontal plane when in the business use posture, whereas the chair seat is inclined at a greater angle of from l0-l5 with respect to the horizontal plane when in the rest posture. 

1. A selectively tiltable chair characterized in that said chair is tiltable between a normally level upright business use posture and a tilted back more restful use posture, comprising a support member carried by a single pedestal support leg disposed generally centrally thereof and having a front end portion extended obliquely upwarD; a chair seat pivotably mounted near a front edge to said front end portion of said support member; a rotary adjustment shaft rotatably mounted on and beneath said chair seat transversely thereacross and having an operation handle fixedly secured thereto; a cam fixedly secured to said rotary shaft for movement therewith and having a generally hookshaped camming slot; a rigid pin fixedly mounted on said support member transversely to the plane of the cam slot with which said cam slot slidably cooperates; and resilient means engagingly interposed between said chair seat and said support member normally tending to bias said seat upwardly to the level use; said pin is normally engaged with the hook tip portion of said cam slot when said seat is in the normal level use to thereby lock said chair with the seat in a substantially horizontal position; and said cam slot being disengageable from said pin responsive to rotational operation of said handle with disengagement of said pin from the hook tip portion of said cam slot, whereby said chair seat is rockable about the pivot at the front end portion of said support member between said two postures with relatively insignificant difference in change of elevation of the front edge of said seat between the two postures.
 2. A chair as defined in claim 1 wherein said hook-shaped slot cam is more L-shaped with the small leg or base of the L directed to the front edge of the seat to constitute the hook portion, and with the longer longitudinal portion disposed generally upright, both portions being slidably cooperable with said transversely mounted pin, particularly when the seat is released into the tilted back more restful use position.
 3. A chair as defined in claim 1 wherein said rotary adjustment shaft is disposed generally medially between the front and a back edge of said seat, and said rigid pin is disposed slightly forward of and generally parallel to said adjustment shaft beneath said chair seat.
 4. A chair as defined in claim 1 wherein said operation handle is extended from said rotary adjustment shaft forwardly along the side of the chair seat terminating near the front edge of said chair seat, and said chair seat resilient means, operation handle and adjustment shaft are so related that upon removal or forward shifting of the chair occupant''s weight forwardly from a relaxed position, the chair seat will automatically return to the normal seat level position.
 5. A chair as defined in claim 1 wherein said support member is formed to have an upwardly open, elongated channel-shaped cross section having a bottom wall and opposite side flanges projecting upwardly therefrom, and directed in a fore and aft direction; said resilient means being interposed between said bottom wall of said support member and the lower surface of the chair seat, and said fixed pin is transversely mounted between the opposite side flanges of said support member while passing through said cam slot.
 6. A chair as defined in claim 1 wherein said resilient means includes a compression coil spring, and means for adjusting the resilient force thereof.
 7. A chair as defined in claim 1 wherein said support, resilient means and chair seat are so related that the chair seat is inclined rearwardly at a shallow angle of 3*-5* with respect to the horizontal plane when in the business use posture, whereas the chair seat is inclined at a greater angle of from 10*-15* with respect to the horizontal plane when in the rest posture. 